In a rolling mill for producing concrete concrete reinforcing bar or at a site at which concrete reinforcing rod is to be cut into shorter lengths and, more generally, wherever bar-like stock may have to be severed into lengths, it is convenient to provide rod shears for this purpose.
Consequently, it is known to provide an apparatus for the cutting of rod stock and especially concrete reinforcing rod, which comprises a conveyor for advancing the rod stock to the cutting site, a shear at the cutting site, and a conveyor downstream of the cutting site for discharging the cut lengths of stock from the apparatus. These three components can be mounted on a common or multipart machine frame or structure. In general, the feed conveyor moves the rod stock in a feed plane, i.e. a horizontal plane through the axis of the bar stock which is located by about half the diameter of the stock above the fixed lower blade of the shear.
Consequently, the shear has a lower blade which is fixed, sometimes referred to as a counter blade, and a movable upper blade which is carried by a slide or carriage and which is spaced above the lower blade to allow the rod stock to pass, and then driven downwardly by conventional means, e.g. an excentric or crank or even a hydraulic or pneumatic driver, to sever the length of stock from the feed.
The stroke, of the upper blade, i.e. the cutting stroke generally is somewhat in excess of the diameter of the rod and is usually in the vertical direction.
Such apparatus can be provided with automatic controls for, for example, measuring the length of stock fed past the shear and then triggering the shear when the desired length has been measured, to cut the stock accurately into respective lengths.
A conventional apparatus of this type has been illustrated and described in German patent document Open Application DE OS No. 30 38 082, that apparatus having no elements which are provided on the shear slide or on the shear bed to cooperate with the feed conveyor to stabilize the depositing of the cut length upon the latter. In this system the discharge plane of the discharge conveyor, i.e. the plane through the center of the rod when the rod lies on the discharge conveyor, coincides with the feed plane.
This arrangement has certain disadvantages. For example, during the cutting process, substantial force may be applied to the rod length which is being severed from the oncoming stock so as to disorient or dislocate this length. The stock then has to pass onto the discharge conveyor and may even be incapable of being reoriented automatically by this conveyor for proper displacement.
Problems are also encountered when pressing rollers form part of the discharge conveyor and engage a leading portion of a cut length of stock. High level disorientation or deflection of the stock can cause damage to the apparatus.
This problem has been recognized and German Pat. No. 33 00 940, for example, has especially designed a conveyor to prevent uncontrolled shifting of the rod material. This is not always successful.
Mention should also be made of the fact that the uncontrolled handling of the rod material may make the subsequent bundling of the rod material, as is often desired, impractical or impossible.